Alex Wong/Getty Images(WASHINGTON) — President Trump said in a tweet Sunday that he is ordering the Department of Justice to “look into” whether his 2016 presidential campaign was improperly “infiltrated or surveilled” for political purposes.

Trump added that he’d ask whether “any such demands or requests were made by people within the Obama Administration.”

The president said he would make the order official on Monday but offered no further details about what form he would expect such an inquiry to take.

The DOJ currently does not have a comment on the tweet.

The tweet is the latest escalation by the president in fueling a narrative that the Trump campaign may have been spied on by the Federal Bureau of Investigation or the DOJ. President Trump has sent out a series of tweets in recent days advancing the theory first voiced by some conservative commentators that the FBI had a spy in the Trump campaign.

The Washington Post and The New York Times have reported in recent days that the FBI sent an informant to talk to several Trump campaign aides during 2016, with the Times citing unnamed sources that these contacts were made only after the FBI had gathered information that the informant’s targets had made suspicious contacts with Russians during the campaign.

On Saturday, the president in a tweet also called for the congressional review or release of classified DOJ documents that have been sought by House Intelligence Committee Chairman Devin Nunes, R-Calif., “regarding a specific individual,” according to a letter the DOJ sent to Nunes rejecting his demand for the information earlier this month.

In rejecting Nunes’ request, the DOJ warned that the disclosure of such information “can risk severe consequences, including potential loss of human lives.”